There's a really bare-bones cheap place in Chinatown called Buddha's Vegetarian at 666 Dundas W.

Simon's Wok @ Logan & Gerrard (similar menu, slightly better ambiance) and Cafe 668 (used to be next door to Buddha's) now at 885 Dundas west of Bathurst. More modern decor, pricier menu, way better food. They'll use garlic and onion if you ask, a big no-no in traditional Buddhist cookery. And not so much deep-fried fake meat with food-colouring.

A bit further east of Buddha's Vegetarian is Full Moon restaurant, also a Chinese vegetarian place. The Chinese name means "the first and fifteenth of the month", meaning the days when casual followers of Buddhism would have vegetarian meals.